Buggy code:
public class LoggingSubsystemParser implements XMLStreamConstants , XMLElementReader < List < ModelNode > > , XMLElementWriter < SubsystemMarshallingContext > { static final LoggingSubsystemParser INSTANCE = new LoggingSubsystemParser ( ) ; private LoggingSubsystemParser ( ) { } @ Override public void readElement ( final XMLExtendedStreamReader reader , final List < ModelNode > list ) throws XMLStreamException { } static void parseLoggerElement ( final XMLExtendedStreamReader reader , final PathAddress address , final List < ModelNode > list , final Set < String > names ) throws XMLStreamException { } static void parseAsyncHandlerElement ( final XMLExtendedStreamReader reader , final PathAddress address , final List < ModelNode > list , final Set < String > names ) throws XMLStreamException { } static void parseRootLoggerElement ( final XMLExtendedStreamReader reader , final PathAddress address , final List < ModelNode > list ) throws XMLStreamException { if ( ( reader . getAttributeCount ( ) ) > 0 ) { throw unexpectedAttribute ( reader , 0 ) ; } final ModelNode node = new ModelNode ( ) ; <START_BUG> node . get ( OP ) . set ( ROOT_LOGGER_ADD_OPERATION_NAME ) ; <END_BUG> node . get ( OP_ADDR ) . set ( address . toModelNode ( ) ) . add ( CommonAttributes . ROOT_LOGGER , CommonAttributes . ROOT_LOGGER_ATTRIBUTE_NAME ) ; final EnumSet < Element > encountered = EnumSet . noneOf ( Element . class ) ; final Namespace namespace = Namespace . forUri ( reader . getNamespaceURI ( ) ) ; while ( ( reader . hasNext ( ) ) && ( ( reader . nextTag ( ) ) != ( XMLStreamConstants . END_ELEMENT ) ) ) { switch ( namespace ) { case LOGGING_1_0 : case LOGGING_1_1 : case LOGGING_1_2 : { final Element element = Element . forName ( reader . getLocalName ( ) ) ; if ( encountered . contains ( element ) ) { throw duplicateNamedElement ( reader , reader . getLocalName ( ) ) ; } encountered . add ( element ) ; switch ( element ) { case CommonAttributes . FILTER_SPEC : case FILTER : { LoggingSubsystemParser . parseFilter ( namespace , node , reader ) ; break ; } case CommonAttributes . LEVEL : { CommonAttributes . LEVEL . parseAndSetParameter ( readStringAttributeElement ( reader , "name" ) , node , reader ) ; break ; } case CommonAttributes . HANDLERS : { LoggingSubsystemParser . parseHandlersElement ( node . get ( CommonAttributes . HANDLERS . getName ( ) ) , reader ) ; break ; } default : throw unexpectedElement ( reader ) ; } break ; } default : { throw unexpectedElement ( reader ) ; } } } list . add ( node ) ; } static void parseConsoleHandlerElement ( final XMLExtendedStreamReader reader , final PathAddress address , final List < ModelNode > list , final Set < String > names ) throws XMLStreamException { } static void parseFileHandlerElement ( final XMLExtendedStreamReader reader , final PathAddress address , final List < ModelNode > list , final Set < String > names ) throws XMLStreamException { } static void parseCustomHandlerElement ( final XMLExtendedStreamReader reader , final PathAddress address , final List < ModelNode > list , final Set < String > names ) throws XMLStreamException { } static void parsePeriodicRotatingFileHandlerElement ( final XMLExtendedStreamReader reader , final PathAddress address , final List < ModelNode > list , final Set < String > names ) throws XMLStreamException { } static void parseSizeRotatingHandlerElement ( final XMLExtendedStreamReader reader , final PathAddress address , final List < ModelNode > list , final Set < String > names ) throws XMLStreamException { } private static void parseFileElement ( final ModelNode node , final XMLExtendedStreamReader reader ) throws XMLStreamException { } private static String parseFormatterElement ( final XMLExtendedStreamReader reader ) throws XMLStreamException { } private static String parsePatternFormatterElement ( final XMLExtendedStreamReader reader ) throws XMLStreamException { } private static void parsePropertyElement ( final ModelNode node , final XMLExtendedStreamReader reader ) throws XMLStreamException { } private static void parseHandlersElement ( final ModelNode node , final XMLExtendedStreamReader reader ) throws XMLStreamException { } static void parseLoggingProfilesElement ( final XMLExtendedStreamReader reader , final PathAddress address , final List < ModelNode > list ) throws XMLStreamException { } static void parseLoggingProfileElement ( final XMLExtendedStreamReader reader , final PathAddress address , final List < ModelNode > list , final Set < String > profileNames ) throws XMLStreamException { } private static void parseFilter ( final Namespace namespace , final ModelNode node , final XMLExtendedStreamReader reader ) throws XMLStreamException { } private static void parseFilterChildren ( final StringBuilder filter , final boolean useDelimiter , final XMLExtendedStreamReader reader ) throws XMLStreamException { } @ Override public void writeContent ( final XMLExtendedStreamWriter writer , final SubsystemMarshallingContext context ) throws XMLStreamException { } public void writeContent ( final XMLExtendedStreamWriter writer , final ModelNode node ) throws XMLStreamException { } private void writeCommonLogger ( final XMLExtendedStreamWriter writer , final ModelNode node ) throws XMLStreamException { } private void writeCommonHandler ( final XMLExtendedStreamWriter writer , final ModelNode node ) throws XMLStreamException { } private void writeConsoleHandler ( final XMLExtendedStreamWriter writer , final ModelNode node , final String name ) throws XMLStreamException { } private void writeFileHandler ( final XMLExtendedStreamWriter writer , final ModelNode node , final String name ) throws XMLStreamException { } private void writeCustomHandler ( final XMLExtendedStreamWriter writer , final ModelNode node , final String name ) throws XMLStreamException { } private void writePeriodicRotatingFileHandler ( final XMLExtendedStreamWriter writer , final ModelNode node , final String name ) throws XMLStreamException { } private void writeSizeRotatingFileHandler ( final XMLExtendedStreamWriter writer , final ModelNode node , final String name ) throws XMLStreamException { } private void writeAsynchHandler ( final XMLExtendedStreamWriter writer , final ModelNode node , final String name ) throws XMLStreamException { } private void writeLogger ( final XMLExtendedStreamWriter writer , String name , final ModelNode node ) throws XMLStreamException { } private void writeRootLogger ( final XMLExtendedStreamWriter writer , final ModelNode node ) throws XMLStreamException { } }

Fix:
node . get ( OP ) . set ( ADD ) ;